Account suspended over disputed charges from a linked account we no longer control - need urgent help

Hi everyone,

Our AWS account has been suspended due to an unpaid invoice. The issue is that the overwhelming majority of that invoice comes from a linked account that we no longer have access to or control over. The charges on that linked account include RDS, EKS, EC2, and ELB resources that we never provisioned. We also previously received a notice from AWS that our account may have been accessed by an unauthorized third party, so we believe these charges are a direct result of that security incident. We have since secured the account by updating credentials and enabling MFA.

We have already opened two support cases (case IDs: *********** and ***********) but both have been left unassigned with no response. Meanwhile our production environment is completely down and active clients are affected.

Has anyone dealt with a similar situation? Specifically:

1. How do you get a billing dispute escalated when support cases aren't being assigned?
2. Can AWS suspend your account over charges from a linked account you don't control?
3. Is there a faster way to reach the billing team without a paid support plan?

Any advice appreciated. This is urgent. Thank you